Fell on pie
From Super-wiki
In her Ten Expressions" Picspam for 2.21 All Hell Breaks Loose: Part One, kroki_refur told an alternate version of the episode where Sam did not die but rather fell on the pie.
The phrase "when Sam fell on pie" became a humorous euphemism for referring to Sam's (temporary) death.
A photo taken during a blogger's visit to the set during the filming of the finale revealed evidence of the pie accident
See also